The present invention relates to a method for improving a tire pressure detection system using indirect measurement.
Motor vehicles with electronic brake systems equipped with an ABS control (ABS: Anti-lock System), driving dynamics control, or systems of this type, frequently include programs for detecting a tire pressure loss which are able to detect such a tire pressure loss exclusively from the fact that rotational speed changes are encountered on the wheels as a consequence of the pressure loss. Further, it is known in the art to evaluate input signals of rotational speed sensors either alone or jointly with other sensors (yaw rate, lateral acceleration, etc.) in order to detect the driving situation.
The invention deals with the problem that spurious alarms in pressure loss detection systems (DDS) with indirect measurement, such as the method disclosed in DE 100 58 140 A1 in particular, become more frequent when the vehicle has a high point of gravity (e.g. due to a roof track) or when a trailer is coupled to the vehicle being equipped with the pressure loss detection system. These indirectly measuring pressure loss detection methods learn so-called reference values, which are basically used for a crosswise comparison of the individual wheels. In a four-wheel vehicle it has e.g. gained acceptance to consider three independent reference values. A first reference value describes the relation between two wheels on one axle, a second reference value describes the relation between two wheels on the same vehicle side, and a third reference value describes the relation between two diagonally opposite wheels.
Tire pressure control systems with indirect measurement per se known in the art such as the system described in DE 199 61 681 A1, admittedly, have been improved already by taking into account driving parameters such as the yaw rate, etc. However, so far individual driving parameters have always been considered separately. A combined consideration of driving parameters is not described in the state of the art.
In view of the above, an object of the invention involves providing a method which improves the prior art indirect tire pressure control systems to such effect that a combination of several driving parameters are taken into account for the detection of tire pressure loss.